46 C.F.R. § 381.9
For purposes of shipping bulk agricultural commodities under programs administered by sponsoring Federal agencies from U.S. Great Lakes ports during the 1996-2000 Great Lakes shipping seasons, if direct all-U.S.-flag service, at fair and reasonable rates, is not available at U.S. Great Lakes ports, a joint service involving a foreign-flag vessel(s) carrying cargo no farther than a Canadian port(s) or other point(s) on the Gulf of St. Lawrence, with transshipment via a U.S.-flag privately-owned commercial vessel to the ultimate foreign destination, will be deemed to comply with the requirement of "available" commercial U.S.-flag service under the Cargo Preference Act of 1954. Shipper agencies considering bids resulting in the lowest landed cost of transportation based on U.S.-flag rates and service shall include within the comparison of U.S.-flag rates and service, for shipments originating in U.S. Great Lakes ports, through rates (if offered) to a Canadian port or other point on the Gulf of St. Lawrence and a U.S.-flag leg for the remainder of the voyage. The "fair and reasonable" rate for this mixed service will be determined by considering the U.S.-flag component under the existing regulations at 46 CFR part 382 or 383, as appropriate, and incorporating the cost for the foreign-flag component into the U.S.-flag "fair and reasonable" rate in the same way as the cost of foreign-flag vessels used to lighten U.S.-flag vessels in the recipient country's territorial waters. Alternatively, the supplier of the commodity may offer the Cargo FOB Canadian transshipment point, and MARAD will determine fair and reasonable rates accordingly.
46 C.F.R. §381.9